JP2017149637A - Hydration acceleration method of steel slag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide slag appropriate for applications such as a road-base material by effective and secure hydration acceleration of steel slag.SOLUTION: A hydration acceleration method of steel slag includes: a crush step 2 of crushing steel slag; a water imparting step 4 of scattering water to the steel slag crushed in the crush step 2 to uniformly impart water to the steel slag; and a steam aging step 3 of steam-aging the steel slag with water imparted at the water imparting step 4. In the water imparting step 4, the steel slag is preferably kneaded after imparting water to the steel slag in an integrated condition or water may preferably be imparted to the steel slag in a non-integrated condition.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to a method for promoting the hydration reaction of steelmaking slag that increases the hydration promotion effect by uniformly applying moisture in advance when steam aging the steelmaking slag.

In recent years, attention has been paid to the use of slag as an earthwork or roadbed material due to problems such as reduction of waste and depletion of natural resources. For applications such as roadbed materials, steelmaking slag and the like discharged from a pretreatment process, a converter, a secondary refining process, and the like are used.
By the way, when using steelmaking slag for the above-mentioned use of roadbed material, an expansion standard obtained by a method defined in JIS A 5015: 2013 (steel slag for roads) so that the roadbed material does not expand after construction ( It is necessary to use steel slag that complies with 1.5%). In addition, when using steelmaking slag for earthwork applications, it is necessary to use steelmaking slag that complies with the expansion standard (1.5%) obtained by the method specified in JSTM 8001 (steel slag crushed stone for earthwork), for example. is there. Therefore, as shown in Patent Document 1 to Patent Document 5, a technique for accelerating the hydration reaction of steelmaking slag in advance to prevent expansion after construction has been developed.

For example, Patent Document 1 discloses that the slag hydration disintegration (expansion) is adjusted by adjusting the maximum particle size to 40 mm or less for the steel slag fertilizer and performing steam aging (4 days) and / or atmospheric aging treatment. An underwater disintegration suppression technique for suppressing converter slag fertilizer is disclosed.
Patent Document 2 discloses that conventional aging treatment is performed by performing steam aging on large converter slag, adjusting the particle size to small lumps, and then performing natural (atmospheric) aging or steam aging. Further, there has been disclosed a converter slag particle size adjustment and expansion suppression technique that significantly reduces the steam consumption basic unit and reduces the expansion rate of the slag.

Patent Document 3 discloses that a converter slag having a particle size of 25 mm or less is immersed in a steam aging treatment and a carbonic acid solution for 72 hours, and the converter slag is carbonated and used as a civil engineering material. A technique for suppressing expansion of slag has been disclosed.
Furthermore, Patent Document 4 discloses a technique for suppressing the expansion of the granulated slag by sprinkling water on the accumulated granulated slag, covering with a water-impermeable coating material after sprinkling, and performing an aging treatment. .

  Furthermore, in Patent Document 5, in the steam aging treatment of steel slag, the water content of the slag is made to be 10% by weight or more, and the water content is applied to a submerged pit having a depth of 1 m in 24 hours. A technique for immersing slag over the surface is disclosed.

JP 2008-247665 A JP-A-6-56487 JP 2010-13315 A JP 2013-256413 A JP-A-8-12384

By the way, in order to ensure the aging with respect to the steelmaking slag, it is necessary to apply uniform and sufficient moisture to the steelmaking slag to be aged.
However, the technique of patent document 1-patent document 3 is not described whether sufficient water | moisture content is uniformly provided to the steelmaking slag which is a process object about the steam aging in steelmaking slag. That is, since moisture is required to promote steam aging, it is unclear whether these methods can sufficiently promote hydration of steelmaking slag.

On the other hand, although the technique of patent document 4 sprays water before steam aging, since water is sprinkled directly from the steelmaking slag piled up, the water sprayed is enough for steelmaking slag. It is not impregnated and the time required for watering tends to be long.
Furthermore, the technique of Patent Document 5 requires a large submerged pit to impregnate the steelmaking slag with water, and the equipment cost tends to be expensive.

  The present invention has been made in view of the above-described problems, and hydrated steelmaking slag capable of efficiently and reliably promoting hydration of steelmaking slag and obtaining slag suitable for applications such as roadbed materials. The purpose is to provide a promotion method.

In order to solve the above problems, the method for promoting hydration of steelmaking slag of the present invention employs the following technical means.
That is, the method for promoting the hydration of steelmaking slag according to the present invention includes a crushing process for crushing steelmaking slag, and water application for uniformly applying water to the steelmaking slag by spraying water on the steelmaking slag crushed in the crushing process. And a steam aging process of steam aging the steelmaking slag to which water has been applied in the water application process.

In addition, Preferably, the said water provision process is good to knead | mix the said steelmaking slag, after providing water with respect to the steelmaking slag made into the accumulation state.
In addition, Preferably, the said water provision process is good to provide water with respect to the steelmaking slag made into the non-accumulation state.
Preferably, when performing the steam aging process, the water content of the steelmaking slag when water is applied in the water application process is changed to slag in the water application process so that the relationship of formula (1) is satisfied. It is preferable to determine the weight L of moisture to be applied.

Preferably, in performing the steam aging step,
The relationship between the water content (X) of the steelmaking slag after water is applied in the water application step and the steam flow rate (Y) during the steam aging treatment satisfies the relationship of the following equations (3) and (4). Thus, it is good to control the moisture content (X) and steam flow rate (Y) of slag after uniform watering.

  According to the method for promoting hydration of steelmaking slag of the present invention, steelmaking slag can be efficiently and reliably promoted to hydrate, and steelmaking slag suitable for applications such as roadbed materials can be obtained.

It is the figure which showed the procedure of the hydration promotion method of the steelmaking slag concerning this embodiment. It is the figure which compared the change of the maximum expansion coefficient of the steelmaking slag with respect to the amount of added water | moisture content by the method of provision of a water | moisture content. It is the figure which compared the change of the minimum expansion coefficient of the steelmaking slag with respect to the amount of addition water by the method of provision of moisture. It is the figure which showed the relationship between the parameter which consists of the moisture content (X) of the steelmaking slag after providing water, and the steam flow rate (Y) at the time of a steam aging process, and a maximum expansion coefficient.

[First Embodiment]
Hereinafter, an embodiment of a method for promoting hydration of steel slag according to the present invention will be described with reference to the drawings.
In addition, the hydration promotion method of 1st Embodiment is applied with respect to steelmaking slag, such as converter slag which is a steel byproduct produced at the time of refining processing in a converter etc. (in slag discharge process 1). Thus, the steelmaking slag can be efficiently hydrated.

Steelmaking slag contains calcium oxide (CaO), silicon dioxide, aluminum oxide, iron and the like. This steelmaking slag is exhausted and generated outside after the refining process and used for various purposes.
By the way, a part of quicklime added to remove unnecessary components such as silicon, phosphorus and sulfur remains in the steelmaking slag after being discharged. This quicklime is called free-CaO (free lime).

The free-CaO on the surface of the steelmaking slag or near the surface reacts with the applied moisture to become calcium hydroxide (Ca (OH) ₂ ). That is, a hydration reaction (CaO + H ₂ O → Ca (OH) ₂ ) is performed on or near the surface of the steelmaking slag, and the volume expands about twice. Furthermore, calcium hydroxide (Ca (OH) ₂ ) is carbonated in the atmosphere to become calcium carbonate (CaCO ₃ ), and the volume expands about 1.1 times.

  In particular, steelmaking slag with a large amount of free-CaO has a high expansibility, and when used as a roadbed material, it may expand due to rainwater or the like, and asphalt may be raised to affect pavement. In addition, when the particle size of the steelmaking slag is large, there is a possibility that poor hydration may occur rarely due to reasons such as difficulty in hydration to the inside and self-collapse due to expansion (exposure of a new surface). Therefore, before shipping as a roadbed material, a hydration promotion method is performed in which steelmaking slag is expanded in advance and the expansion when used as a roadbed material or the like is suppressed.

  There are various methods for promoting hydration. For example, there are those having a crushing step 2 for crushing steelmaking slag and a steam aging step 3 for promoting the expansion of the steelmaking slag by applying steam to the crushed steelmaking slag. is there. In the promotion method of this method, the steelmaking slag crushed to a particle size of 0 to 40 mm in the crushing step 2 is stacked in a slag storage area (temporary storage area) and then loaded in an aging pit (steam aging treatment area). Attached.

Steam is supplied to the steelmaking slag stacked in the aging pit from the bottom of the aging pit, and the expansion of the steelmaking slag is promoted by the action of the steam.
By the way, as described in “Problems to be Solved by the Invention”, even if an attempt is made to expand steelmaking slag in advance using steam, if the moisture content of the slag before steaming is small, the effect of aging is ineffective. In addition, if the moisture content of the slag is partially small, unevenness occurs in the way of aging, resulting in a difference in the expansion behavior of the steelmaking slag, and water that is the standard value of JIS A 5015 2013 There is a risk of exceeding the dip-expansion ratio (expansion rate), which may make it difficult to use as a roadbed material. Furthermore, the water immersion expansion ratio (expansion rate), which is the standard value of JSTM H 8001, may be exceeded, which may make it difficult to use as an earthwork material.

Therefore, in the present invention, the water application step 4 is performed in which water is uniformly sprayed and applied to the steelmaking slag crushed in the crushing step 2. If the steelmaking slag is uniformly moistened in advance by such a water application step 4, the hydration promotion reaction occurs uniformly in the steam aging step 3, so that the steelmaking slag can be reliably expanded.
Hereinafter, the method for promoting hydration of steelmaking slag according to the present embodiment will be described with reference to FIGS.

As shown in FIG. 1, the method for promoting hydration of steelmaking slag according to the present invention is uniformly applied to the steelmaking slag by spraying water to the crushing process 2 for crushing the steelmaking slag and the steelmaking slag crushed in the crushing process 2. It has the water provision process 4 which provides water, and the steam aging process 3 which carries out steam aging of the steelmaking slag to which water was provided in the water provision process 4.
Specifically, in the water application step 4 of the present invention, the steelmaking slag that has been put into an accumulated state is kneaded with the steelmaking slag after water has been added to the steelmaking slag that has been put into a non-accumulated state. One or both of “applying water in a sprayed state” are performed.

In the following, the hydration promotion method of the present invention will be described by taking an example of “applying water in a sprayed state to a steelmaking slag in a non-accumulated state” as a first embodiment.
The crushing step 2 described above is a step of continuously crushing steelmaking slag discharged from a converter or the like using a crusher. Generally, in the crushing process of the present invention, a mobile crusher or the like is used, and the steelmaking slag crushed by the crusher is refined to a particle size of 0 to 40 mm. And the refined steelmaking slag is sent to an aging pit by a conveyor belt, or piled up in a slag storage area in a mountain shape. The water application process 4 is performed at the time of conveyance by this conveyor belt, or at the time of stacking to a slag storage place.

  In the water application step 4, water is applied in a sprayed state to the steelmaking slag that has been made fine and non-laminated. This “non-laminated state” means a state in which a large amount of fine steelmaking slag is not stacked, that is, a state in which it is thinly stacked, and it is transported horizontally in a thinly stacked state or a thin curtain The case where it is falling vertically in such a state is shown. Note that the thickness of the thin volume state or the state of a thin curtain is preferably 50 cm or less, more preferably 30 cm or less, and most preferably 10 cm or less.

  For example, if the refined steelmaking slag is piled up in the slag storage area, the crushed steelmaking slag will fall continuously from the top to the slag storage area in order from the crushed material. It will be piled up. That is, the steelmaking slag that is piled up and piled up in the slag yard in this way, in other words, the steelmaking slag that falls vertically in a thin state like a curtain is the `` non-stacked state '' of this embodiment Steelmaking slag. And, to the steelmaking slag falling to the slag storage site etc., it is possible to continuously give water to the steelmaking slag from the side or the spray part installed above in the form of a spray in the “non-laminated state” in the first embodiment. It is an example of “giving water”.

  In addition, when transporting fine steelmaking slag to the aging pit using a conveyor belt or the like, the crushed steelmaking slag is continuously stacked on the conveyor belt in order from the crushed one. It will be transported. That is, the steelmaking slag that is thinly stacked and carried on the conveyor belt in this way also becomes the “non-laminated” steelmaking slag of the present embodiment. In addition, in the first embodiment, water is sprayed continuously on the steelmaking slag conveyed in the horizontal direction on the conveyor belt. This is another example of “grant”.

  Specifically, in the water application step 4 described above, 0.5 wt% to 10 wt% of water is applied to the steelmaking slag per unit weight in a non-laminated state. In this way, the water content of the steelmaking slag after the application of water, in other words, the steelmaking slag supplied to the steam aging process 3, is uniformly 2.5 wt% or more with respect to the piled steelmaking slag, preferably It can be 5 wt% or more, more preferably 8 wt% or more.

As described above, when water is applied to the steelmaking slag in a non-laminated state, the water is evenly distributed throughout the steelmaking slag, and water can be contained in the entire slag. As a result, it becomes difficult for the aging effect of the steelmaking slag to occur at each part of the pile, and it is possible to generate slag having a low expansion coefficient in the entire steelmaking slag.
Moreover, since such a water provision process 4 is performed according to conveyance of the steelmaking slag after crushing, it is not necessary to newly provide the manufacturing equipment which performs only the water provision process 4, and even if it provides the water provision process 4 There is no worry that the time will be significantly longer than in conventional hydration promotion methods.

In this way, the steelmaking slag to which water has been uniformly applied in the water application step 4 is conveyed to the aging pit and steam-aged in the aging pit.
In the steam aging process 3, steam is supplied toward the steelmaking slag from below the steelmaking slag (lower part of the aging pit) with respect to the steelmaking slag stacked in the aging pit, and the steam supplied into the steelmaking slag is supplied. It is the process of using and hydrating steelmaking slag. If steelmaking slag is supplied to such a steam aging process 3, the free-CaO of steelmaking slag will raise | generate a hydration reaction by the effect | action of a steam, and the expansion of the steelmaking slag after a process can be suppressed.

Specifically, the above-described steam aging process 3 is processed in a processing time of 24 hr to 96 hr, although the length of the processing time varies depending on the operation status. In addition, during the steam aging process, not only the above-described steam but also liquid water may be provided in a sprayed manner as appropriate.
As described above, the moisture content of the steelmaking slag when moisture is applied in the moisture application step 4 is 2.5 wt% or more, preferably 5 wt% or more, more preferably 8 wt% or more. The weight L (kg) of the water supplied to the steelmaking slag in step 4 can be determined as follows using the following formula (1).

That is, if the weight W (kg) of the steelmaking slag processed in the steam aging process 3 is determined, the weight L (kg) of the water supplied to the steelmaking slag in the moisture application process 4 can be determined.
Moreover, if water is applied to the steelmaking slag in a non-laminated state as described above, the water can be evenly distributed throughout the steelmaking slag, and water can be contained in the entire slag. As a result, the air permeability between the accumulated slags becomes good, and the amount of steam used in steam aging can be reduced. In addition, the relationship between the water content X (wt%) and the steam flow rate Y (t / h · t-slag) of the steelmaking slag capable of suppressing the expansion after the treatment has been found, and the following equations (3) and (4) Can be used to determine the optimum water content X (wt%) and steam flow rate Y (t / h · t-slag).

  Note that the upper limit of the parameter “60 × ((0.7 × X) + (Y))” in the formula (3) is 650 or less, preferably 600 or less, more preferably 550, more preferably, depending on the operation status. Is preferably 500. Further, the lower limit of the parameter “60 × ((0.7 × X) + (Y))” may be 150 or more, preferably 200 or more, more preferably 250 or more, and still more preferably 300 or more.

On the other hand, the lower limit (wt%) of the moisture amount X in the formula (4) is preferably 2.5 wt% or more, preferably 5 wt% or more, more preferably 8 wt% or more. (t / h · t-slag) is 1.0 t / h · t-slag or more, preferably 1.5 t / h · t-slag or more, more preferably 2.5 t / h · t-slag or more. Is good.
According to the hydration promotion method of the first embodiment described above, moisture can be uniformly applied to the entire steelmaking slag in advance before steam aging, and the hydration promotion effect of the steelmaking slag can be greatly increased. Therefore, it is possible to manufacture a slag having a low expansion coefficient.

As a result, by promoting slag hydration reaction (inhibition of expansion), it becomes possible to promote the use of slag as a material and to effectively use the by-product.
Moreover, if the hydration promotion method of the first embodiment described above is performed, the hydration of the steelmaking slag subjected to the steam aging process 3 is sufficiently promoted, and therefore, it is one of the methods for promoting the hydration of steelmaking slag. The atmospheric aging process 5 shown in FIG. 1 may be performed or may not be performed. That is, in the hydration promotion method of the first embodiment, it is not always necessary to perform the air aging process 5, and the process can be simplified.
[Second Embodiment]
In the hydration promotion method of the second embodiment, the crushing step 2 and the steam aging step 3 are the same as those in the first embodiment, but the water application step 4 is different from the first embodiment.

That is, the water application step 4 of the second embodiment is “kneading the steelmaking slag after applying water to the steelmaking slag in an accumulated state”.
Specifically, in the water application step 4 of the second embodiment, water is sprayed on the steelmaking slag stacked in an aging pit, a slag yard, etc., and then the steelmaking slag to which the water is applied is used using a heavy machine such as an excavator. Stirring and kneading.

Instead of stirring and kneading steelmaking slag with a heavy machine, steelmaking slag to which water has been added may be kneaded using a kneader such as a pug mill.
In this way, the added water can be forcibly kneaded together with the steelmaking slag, and the applied water can be evenly distributed throughout the steelmaking slag pile, and water is included in the entire steelmaking slag. It becomes possible. As a result, the aging effect does not easily vary as in the first embodiment, the air permeability between the slags is improved, the steam flow rate can be reduced, and a slag having a low expansion coefficient as a whole can be produced. It becomes like this.

  In addition, about the structure of the process other than the water provision process 4 in 2nd Embodiment, and an effect, it does not change from 1st Embodiment. Therefore, the description about these is abbreviate | omitted.

Next, the effects of the hydration promoting method of the present invention will be described in more detail using Examples and Comparative Examples.
In Examples and Comparative Examples, the water application process 4 is performed while changing the water application method and the amount of water applied to the steelmaking slag (converter slag) adjusted to a particle size of 0 to 40 mm by a crusher. After that, the steel slag subjected to the water application step 4 under each condition is subjected to steam aging treatment under the same aging conditions.

Specifically, Example 1 to Example 8 performed the water application step 4 under the conditions corresponding to the above-described first embodiment, and Examples 9 and 10 were water under the conditions corresponding to the second embodiment. Application step 4 is performed.
In Comparative Examples 1 to 3, the steelmaking slag after crushing is piled up to form a pile, and then water is applied directly from the top of the pile. It is what is indicated by.

  Moreover, the water application process 4 corresponding to 1st Embodiment is the above from the upper part with respect to the steelmaking slag conveyed on a conveyor belt, when conveying the steelmaking slag after crushing from a crusher to a temporary placement place with a conveyor belt. It is a spray of water. The water application step 4 corresponding to the first embodiment is shown in Table 1 as “applying water between crushing and stacking”.

Furthermore, the water provision process 4 corresponding to 2nd Embodiment sprays water first with respect to the steelmaking slag piled up in the aging pit or the slag storage place, and then knead | mixes steelmaking slag with a heavy machine, Table 1 In “Kneading steelmaking slag after adding water”.
In addition, the amount of water given under each condition is as described in “Amount of added water” in Table 1. That is, the water supply process 4 gives the water | moisture content which becomes the ratio of 0.5 wt%-10 wt% by weight ratio with respect to the steelmaking slag before water provision.

  In addition, how much moisture is contained in the steelmaking slag is to collect a steelmaking slag sample from a plurality of parts located in the pile of steelmaking slag, and to a steelmaking slag sample collected from a plurality of parts, The moisture content specified in JIS A 1203 “Method based on soil moisture content test” was measured. Specifically, with respect to the piles of steelmaking slag, the amount of moisture (27 parts) obtained by dividing the piles into three equal parts in the width direction, the height direction, and the depth direction and equally dividing the piles ( The water content was measured. Among the measurement results at 27 locations, the highest moisture content is the one with the highest moisture content, the “minimum moisture content” is the one with the lowest moisture content, and the average value of the moisture content at the 27 locations is “ It was shown in Table 1 as “average moisture content”.

In addition, the moisture content may be measured and evaluated by using a near-infrared moisture meter instead of the weight before and after drying as in JIS described above.
The steelmaking slag having different water application conditions and application amounts was steam-aged under the aging conditions shown in Table 1 “Processing conditions”. In addition, the steam aging of the steelmaking slag of an Example and a comparative example was performed using the pit (aging conditions from which the processing amount of steelmaking slag differs) from which size differs.

  That is, for a steam aging treatment method with a steelmaking slag throughput of 0.06 t, a sample of 60 kg of steelmaking slag is accommodated in a cylindrical container having an inner diameter of 400 mm and a length of 720 mm controlled by the above-described actual machine aging treatment conditions. It is what I did. Specifically, the steelmaking slag was steam-aged at a treatment temperature of 75 to 95 ° C. and a treatment time of 24 to 96 hours.

Further, the temperature during the treatment is measured using a sheath K thermocouple, and the position where 50 mm is inserted in the depth direction from the top of the accommodated slag is measured, and the variation in the treatment temperature becomes ± 1.0 ° C. or less. Moreover, about the steam aging processing method with a throughput of 1000 t of steelmaking slag, 1000 t of steelmaking slag is charged into a rectangular pit having a length of 23.5 m, a width of 8.4 m, and a height of 3.3 m, A plurality of steam pipes are arranged in parallel at the bottom of a pit where steelmaking slag is piled up, and the steam pipes are provided with steam outlets at regular intervals. Specifically, the steelmaking slag was steam-aged at a treatment temperature of 100 ° C. and a treatment time of 48 hours.

  In addition, the temperature during the treatment is measured using a thermocouple, the position where 250 mm is inserted in the depth direction from the top of the accommodated slag is measured, and the variation in the treatment temperature is ± 1.0 ° C. or less. Processed. For steelmaking slag after steam aging treatment of 0.06t and 1000t, the expansion rate (water) specified in JIS A 5015: 2013 “Steel slag for roads, Appendix 2 Method of water immersion expansion test for steel slag” (Expansion ratio) was measured. That is, steelmaking slag was immersed in water at 80 ° C., and the immersion was continued until the expansion was saturated. And the expansion coefficient X shown by Formula (2) after water immersion expansion was measured by N = 3.

  Of the three measured expansion rates, the one with the highest expansion rate was designated as “maximum expansion rate”, and the one with the smallest expansion rate was designated as “minimum expansion rate”. The results of “maximum expansion rate” and “minimum expansion rate” are shown in Table 1.

  Looking at “Comparative Example 1” to “Comparative Example 3” in Table 1, in “Comparative Example 1” to “Comparative Example 3” in which “water is sprayed directly on the pile after stacking”, the average moisture content increases. However, the moisture content varies, and the “maximum expansion rate” is 4.0% to 4.3%, which is 1.5% which is the acceptance criterion for the expansion rate specified in JIS A 2015: 2013. On the other hand, the “minimum expansion rate” is 0.4% to 1%, and there is a large difference between the “maximum expansion rate” and the “minimum expansion rate”. From this, it can be seen that when “spray water directly on the pile after piled up”, the effect of promoting hydration (inhibition of expansion) is uneven and uneven even when steam aging is performed.

  In the above-mentioned “Comparative Example 1” to “Comparative Example 3”, the “maximum expansion coefficient” is 4.0% to 4.3%, whereas the “minimum expansion coefficient” is 0.4% to It is 1%, and there is a large difference between the values of “maximum expansion coefficient” and “minimum expansion coefficient”. From this, it is determined that when “spray water directly on the pile after piled up”, the effect of hydration promotion (expansion suppression) by steam aging on the steelmaking slag varies greatly from part to part.

  However, “Example 1” to “Example 8” in which the water application condition is “applying water between crushing and stacking”, and the water application condition is “after steel is added to the steelmaking slag. In “Example 9” and “Example 10” which are “kneading”, since the variation in moisture is small and the moisture is increased, the effect of promoting hydration (expansion suppression) is uniform. ”Is 0.5% to 1.4%, which is less than 1.5% which is the acceptance criterion for the expansion coefficient. Such a tendency that “the maximum expansion coefficient of the example is lower than that of the comparative example” is more than the level of the white circle of the comparative example shown in FIG. It is clearly judged from the point that the level of the square is lowered.

Therefore, when the water application condition is “apply water between crushing and stacking” or “kneading the steelmaking slag after applying water”, the steelmaking slag in the water application step 4 before steam aging It can be seen that water is uniformly applied to the water, and the hydration expansion is sufficiently performed in the steam aging process 3 subsequent to the water application process 4.
In “Example 1” to “Example 10”, the difference between the “maximum expansion rate” and the “minimum expansion rate” is at most 0.2%. There is almost no difference from “rate”. This tendency is clearly judged from the point that the levels of the black diamonds, triangles, and squares in the examples take almost the same values in both FIG. 2 and FIG. Compared to the level of this example, the level of the white circle in the comparative example is greatly different between FIG. 2 and FIG.

From this, if the water provision process 4 of this invention is performed, it will be judged that the effect of the hydration promotion (expansion suppression) by the steam aging with respect to steelmaking slag is equalized.
From the above, it is judged that if the water application step 4 of the present invention is performed, the slag suitable for applications such as roadbed materials can be obtained by efficiently and reliably promoting hydration of the steelmaking slag.
On the other hand, in “Example 1” to “Example 10” described above, the “steam amount (steam flow rate)” during steam aging was 1.0 (t / ht-slag). In order to investigate the effect of steam aging conditions on the expansion rate, the “steam volume” was changed in the range of 2.5 (t / ht-slag) to 9.0 (t / ht-slag), and after sprinkling The slag water content, in other words, the “average moisture content” of the slag was changed in the range of 0.5 wt% to 10.5 wt% to evaluate how the maximum expansion coefficient and the minimum expansion coefficient changed.

  As shown in FIG. 4, when the “average moisture content” of slag is (X) and the steam flow rate during steam aging treatment is (Y), the parameter “60 × ((0.7 × X) + (Y )) ”And the maximum expansion coefficient, it was found that when the parameter is in the range of 150 or more, the maximum expansion coefficient is 1.5% or less. In addition, it has been found that the value of the expansion coefficient is constant in the range of 650 or more, that is, 650 or more is an excessive processing condition. Therefore, it has been found that the maximum expansion rate can be efficiently suppressed to 1.5% or less when the parameter is in the range of 150 to 650.

Therefore, if the “average moisture content” of the slag and the steam flow rate (Y) during the steam aging treatment are controlled so as to satisfy the expressions (3) and (4) described above, the expansion of the slag can be efficiently performed. It can be seen that the rate can be reduced such that the maximum expansion rate is 1.5% or less.
This is because, when performing steam aging treatment of slag, when water is uniformly applied to the slag before the steam aging treatment to promote hydration of the slag uniformly, the expansion rate of the slag is lowered and further accumulated. Since the air permeability between the slags is improved, the air permeability of the steam between the slags is improved, and it is considered that the steam contacts the slag uniformly and the expansion rate of the slag can be greatly reduced.

Moreover, by such steam aging treatment, the expansion characteristics of the slag are stabilized, and the steelmaking slag can be used more effectively.
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. In particular, in the embodiment disclosed this time, matters that are not explicitly disclosed, for example, operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component deviate from a range that a person skilled in the art normally performs. Instead, values that can be easily assumed by those skilled in the art are employed.

1 Slag draining process 2 Crushing process 3 Steam aging process 4 Water application process 5 Atmospheric aging process

Claims (5)

Crushing process for crushing steelmaking slag;
A water application step of spraying water on the steelmaking slag crushed in the crushing step, and uniformly applying water to the steelmaking slag;
A steam aging process for steam aging the steelmaking slag to which water has been applied in the water application process;
A method for promoting the hydration of steelmaking slag, characterized by comprising:   2. The method for promoting hydration of steelmaking slag according to claim 1, wherein in the water application step, the steelmaking slag is kneaded after adding water to the steelmaking slag in an accumulated state.   The method for promoting hydration of steelmaking slag according to claim 1, wherein in the water application step, water is applied to the steelmaking slag in a non-accumulated state. In performing the steam aging process,
The weight L of water to be applied to the slag in the water application step is determined so that the water content of the steelmaking slag after the application of water in the water application step satisfies the relationship of formula (1). The method for promoting hydration of steelmaking slag according to any one of claims 1 to 3.
In performing the steam aging process,
The relationship between the water content (X) of the steelmaking slag after water is applied in the water application step and the steam flow rate (Y) during the steam aging treatment satisfies the relationship of the following equations (3) and (4). Thus, the water content (X) and steam flow rate (Y) of slag after uniform watering are controlled, The hydration promotion method of the steelmaking slag in any one of Claims 1-4 characterized by the above-mentioned.